Device for adapting a stop to a sheet stack edge in a sheet processing machine, in particular a printing press

ABSTRACT

A device for setting a stop for a sheet stack in a sheet processing machine includes a provision for the stop to be set obliquely against an oblique stack edge.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority, under 35 U.S.C. §119, of German Patent Application DE 10 2005 051 299.2, filed Oct. 26, 2005; the prior application is herewith incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a device for setting a stop against a stack edge in a sheet processing machine, in particular a printing press.

During stack formation in the delivery of sheet processing machines, it is possible for the front and rear edge of the forming stack not to be parallel. The reason therefor can be cut tolerances during paper cutting from a roll or else different deformations of the sheet over its sheet width due to a different level of ink coverage. However, as a rule, the stops which are critical for the stack formation at the front and rear edge of the stack are parallel and also move only in parallel, so that compensation for non-parallel front and rear edges is not possible. As a result, stacks which do not quite have accurate edges can be produced, which then normally additionally have to run over a vibrating table for further processing.

European Patent EP 0 248 372 B1, corresponding to U.S. Pat. No. 4,813,661, has disclosed a device which, on the stop for the rear stack edge, has brushes with bristles pointing obliquely downward into the stacking region. The brushes are intended to press the falling sheets against the front edge stop.

European Patent EP 0 254 837 B1, corresponding to U.S. Pat. No. 4,828,246, discloses adjustable brushes on the rear edge stop, which move in a pivoting manner as the intermediate stacking device is controlled up and down.

In that case, the pivoting movement is carried out about an axis disposed transversely with respect to the sheet transport direction and disposed parallel to the front edge stops.

SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a device for adapting a stop to a sheet stack edge, in particular a rear edge, running obliquely, in a sheet processing machine, in particular a printing press, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type.

With the foregoing and other objects in view there is provided, in accordance with the invention, a device for sheet stack formation in a sheet processing machine. The device comprises a stop mounted to be set against a stack edge obliquely relative to a sheet transport direction.

In accordance with another feature of the invention, a rear edge stop for a sheet stack in a delivery can also be set obliquely with respect to front edge stops, so that a stack that is not straight can be produced.

In accordance with a further feature of the invention, the device for adapting the sheet edge stop is disposed in such a way that its format can be adjusted, so that different format lengths can be processed. The format adjustment can be carried out by a motor and can therefore be driven with remote adjustment from a control computer of the sheet processing machine.

In accordance with a concomitant feature of the invention, it is additionally possible to use separate motors, which are each disposed on a respective side of the sheet stack and drive a common crossmember or axle for the stops. In this way, both the format adjustment and the oblique setting of the stops can be carried out automatically.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in a device for adapting a stop to a sheet stack edge in a sheet processing machine, in particular a printing press, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic, longitudinal-sectional view of a sheet processing rotary printing press;

FIG. 2 is an enlarged, fragmentary, side-elevation view of a rear edge stop with format and oblique adjustment;

FIG. 2A is a top-plan view of the rear edge stop according to FIG. 2;

FIG. 3 is a fragmentary, side-elevation view of a rear edge stop with motor format setting and manual oblique setting;

FIG. 3A is a top-plan view of the rear edge stop according to FIG. 3;

FIG. 4 is a fragmentary, side-elevation view of a rear edge stop with motor format adjustment and oblique adjustment; and

FIG. 4A is a top-plan view of the rear edge stop according to FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a machine for processing sheets 7, for example a printing press 1, which has a feeder 2, at least one printing unit 3 and 4 and a delivery 6. The sheets 7 are removed from a sheet stack 8 and, separated or overlapping, are fed to the printing units 3 and 4 over a feed table 9. The printing units each contain a plate cylinder 11, 12, in a known manner. The plate cylinders 11 and 12 each have devices 13, 14 for fixing flexible printing plates. Furthermore, each plate cylinder 11, 12 is assigned a device 16, 17 for semiautomatic or fully automatic printing plate change.

The sheet stack 8 lies on a stack board 10 which can be raised under control. The removal of the sheets 7 takes place from an upper side of the sheet stack 8 through the use of a suction head 18, as is known. The suction head 18, inter alia, has a number of lifting and dragging suckers 19, 21 for separating the sheets 7. Furthermore, blowing devices 22 are provided to loosen the upper sheet layers, and sensing elements 23 for stack tracking. A number of side and rear stops 24 are provided in order to align the sheet stack 8, in particular the upper sheets 7 of the sheet stack 8.

Following sheet processing, the sheet 7 is deposited on a sheet stack 27 in the delivery 6 of the sheet processing machine through the use of a gripper system 26, in particular through the use of a chain gripper system in the exemplary embodiment. At least one front edge stop 28 and at least one rear edge stop 29 ensure good stack formation.

According to FIGS. 2 and 2A, the rear edge stop 29 is formed as a crossmember and in each case is held in a holder 31, 32 at the side of the sheet stack 27. The rear edge stop or crossmember 29 has a height which provides a stop surface for a plurality of rear sheet edges 30. The holders 31, 32 are each fixed to a respective actuating device 33, 34 that can be moved linearly in and counter to the sheet transport direction. Each actuating device or format adjusting device is preferably a belt drive having an endlessly circulating belt 35, 40, two deflection rollers 36, 38 and drive rollers 37, 39 for the belts 35, 40. An actuating motor 41, 42, which is provided for each drive roller 37, 39, can be driven by a machine control system for setting purposes.

In the event of a rear edge running obliquely with respect to the front edge of a sheet, the rear edge stop 29 is accordingly set obliquely, by making movement travels of the holders 31 and 32 appropriately different. The result of an oblique setting of the crossmember 29 is a small length change as compared with a crossmember 29 disposed parallel to the front stops 28. This is compensated for by a slot/pin coupling 46, which is provided on one side of the crossmember 29. Only a hole/pin coupling 47 is provided on the opposite side.

In the second exemplary embodiment according to FIGS. 3 and 3A, provision is made to interconnect the actuating devices 33, 34 through the use of a synchronization shaft 48, so that only a single actuating motor 49 is needed for a format adjustment of the rear edge stop 29.

The oblique adjustment can be set separately from the format setting of the rear edge stop 29. For this purpose, the mounting of the crossmember 29 on the holder 32, specifically the slot/pin coupling, is replaced by a stop/spring system 51, 52, 53. In this case, a free end 50 of the crossmember 29 is supported on a horizontally oriented guide 51 and is pressed against a spring 53 through the use of an adjustable stop 52. The stop 52 is disposed in such a way that it can be adjusted manually or remotely through the use of an actuating motor 54 under the control of the machine control system.

During an oblique adjustment of the crossmember 29, the free end 50 of the crossmember 29 is pivoted about a pivot point A, which is formed by the hole/pin coupling 47.

In a simple embodiment according to FIGS. 4 and 4A, provision is made to mount the crossmember 29 on both sides of the sheet stack 27 in such a way that it can be displaced in the sheet transport direction in each of the holders 31, 32 by applying a force for displacing the crossmember 29 in the holders 31, 32 with respective springs 56, 57, which are supported on the holders 31, 32. The holders 31, 32 are each disposed on the adjustable-format devices 33, 34. 

1. A device for sheet stack formation in a sheet processing machine, the device comprising: a stop mounted to be set against a stack edge obliquely relative to a sheet transport direction.
 2. The device according to claim 1, wherein said stop is mounted to be adjustably set against the stack edge.
 3. The device according to claim 1, wherein said stop is a continuous crossmember disposed substantially transversely relative to the sheet transport direction.
 4. The device according to claim 3, which further comprises format adjusting devices, said continuous crossmember being disposed on said format adjusting devices at two sides of the stack.
 5. The device according to claim 1, which further comprises format adjusting devices, said stop being disposed on said format adjusting devices at two sides of the stack.
 6. The device according to claim 5, wherein said format adjusting devices are drivable independently of each other.
 7. The device according to claim 5, wherein said format adjusting devices are drivable in synchronism with each other.
 8. The device according to claim 7, which further comprises an additional actuating device for one end of said stop, said additional actuating device being disposed on one of said format adjusting devices.
 9. The device according to claim 5, wherein said stop is adjustable manually.
 10. The device according to claim 6, wherein said stop is adjustable manually.
 11. The device according to claim 7, wherein said stop is adjustable manually.
 12. The device according to claim 8, wherein said stop is adjustable manually.
 13. The device according to claim 5, wherein said stop is adjustable by a motor.
 14. The device according to claim 6, wherein said stop is adjustable by a motor.
 15. The device according to claim 7, wherein said stop is adjustable by a motor.
 16. The device according to claim 8, wherein said stop is adjustable by a motor.
 17. The device according to claim 5, wherein said stop is adjustable manually and by a motor.
 18. The device according to claim 6, wherein said stop is adjustable manually and by a motor.
 19. The device according to claim 7, wherein said stop is adjustable manually and by a motor.
 20. The device according to claim 8, wherein said stop is adjustable manually and by a motor.
 21. The device according to claim 1, which further comprises springs exerting a force pressing said stop against the stack edge. 